Electrical etching machine



Oct. 17, 1939. R. w. HEISLER ELECTRICAL ETCHING MACHINE Filed Nov. 5, 1936 2 Sheets-Sheet 1 Wm W w n ATTORNEY.

Patented Oct. 17, 1939 UNITED STATES PATENT OFFICE ELECTRICAL ETOHING MACHINE Bay W. Heisler, Kansas City, Mo. Application November 5, 1936, Serial No. 109,321

10 Claims.

This invention relates to electrical etching maplate without the customary movement of the same for the purpose of agitating the bath and overcoming unevenness of depth. 1

Other objects of, the invention include the unique manner in which the broad concepts are embodied in strong, durable and efiective mechanisms, and such minor objects will appear dur ing the course of the following specification, referring to the accompanying drawings, wherein one embodiment of the invention is illustrated.

Figure 1 is a vertical, substantially central section through an etchingmachine made in accordance with the present invention.

Fig. 2 is a top plan view of the same. Fig. 3 is a vertical cross section, taken along line III--III of Fig. 1.

' Fig. 4 is an enlarged, fragmentary, detailed, sectional view along line IV -IV of Fig. 3.

Fig. 5 is a similar view, taken'along line V-V of Fig. 4, and,

Fig. 6 is an enlarged, fragmentary, detailed, sectional view, taken along line VI-VI of Fig. 1.

In describing the embodiment of the invention exemplified, like reference numerals will be used to indicate similar parts throughout the several views, and the numeral 8 designates a tank that may be made up of any suitable material to contain the bath or electrolyte of the nature well known in the art. This bath may be a strong solution of salt water, but it is conceivable that other chemicals might be employed to attain the desired end. As an example, the electrolyte may be composed of salt and water with any desired acid, for example hydrochloric, which breaks up into chlorine and sodium ions. The sodium ions combine with the oxygen and hydrogen in the bath to form sodium hydroxide. Part of the hydrogen in the bath is given off as a gas at the cathode plate. The chlorine ions combine with the copper ions on the plate being etched to form copper chloride which is pulled away from the platetoward the cathodeand precipitated in the bath.

The special type of agitation employed herein is to gently but positively and directly move the chlorine ions against the plate so that they may act thereon.

I The hydrogen gas which forms on the cathode is dislodged by the action of the air jets that are directed thereagainst.

The plate I0, to be etched, is mounted upon a suitable plate holder l2, that in turn is carried by plate support M, which is disposed in tank 8 in such manner as to hold plate l0 in a vertical plane. Plate holder l2 has a metallic connection in the form of a silver contact band l6, so that when thumb: screw I8 is tightened a good electrical contact is created. Plate holder l2 should be adjustable, and to that end its body is provided with a slot 20 that carries band IS. A shelf 24 along one end .of the body of plate holder I2 is grooved to receive the edge of plate l0 and the notch formed in block 22 receives the upper edge of plate support I4 when in the normal position.

Plate support M is mounted for movement in a path of travel perpendicular to the vertical plane of plate In and the mounting of this plate support may comprise runways 26, carried on opposite edges of tank 8, for the reception of blocks 28 that carry support M. These blocks have a longitudinal tongue 30 that extends into groove 32 of runway 26 and a rack 34 engages pinion 36 that is set .into a cavity 38 formed in runway 26.

There is a pinion 36 for each block 28 and a connecting shaft 40 has an operating knob 42 at one end thereof so that when shaft 40 is rotated, both blocks 28 will be moved simultaneously in like directions. A roller 44 carried by clip 46, maintains pressure upon block 28 so that rack and pinion 34 and 36 respectively will not become disengaged during the operation. Plate support l4 depends from one end of blocks 28 and braces 48 serve to lend rigidity to the entire assembly.

Ordinarily, cathodes in machines of this character are in form of plates and the distances between the plate being etched and the cathode are set. It is found thata cathode of greatly reduced surface may be placed anywhere in the electrolyte if the electricalinput is arranged to suit. For plates of relatively large sizes more of the cathode is immersed.

The specially formed cathode 50 hangs in tank 8, and is provided with means for movement to and from the completely lowered position within the electrolyte. This cathode 50 comprises a U- shaped body, made by forming a metal bar, as

illustrated in Fig. 1. The legs 52 of the ushaped body project upwardly through bearings 54, rigid to tank 8, and a rack 58, formed on each as shown in Fig. 1; that is, the rod is formed into a serpentine path that creates a number of salients, all extending to one side of a straight line connecting the lower ends of legs 52. Central salient 62 extends outwardly much farther than salients 64 to each side thereof, and the legs of all these U-shaped salients are preferably parallel to each other and in the same plane. As the cathode is lowered, central salient will first enter the electrolyte, after which the bights to the salients of each side will enter the electrolyte to submerge a progressively greater amount of the length of the cathode.

Obviously, a greater amount of the width of the cathode, as well as the length, is submerged and thereby the electrical action between plate I8 and cathode so is altered to suit conditions with respect to the size of plate I8 and the character of etch desired. A bus bar 88 may connect the ends of legs 52 of cathode 58, and this bus barjthen joined through any suitable con-- nection 68 to the negative pole of a source of electrical energy. The positive pole of this source of energy is placed in connection with plate I8 through the medium of a bar 18 that is mounted upon the outside of tank 8. A number'of clips I2,are on this bar 18 'so that several connections might be made directly to plate I8 if its sizerequires. A'connector I4 joins bar I8 with the electrical source. Bar 18 is in turn placediin connection with plate l8 through any desirable conduit that slips jover pin I8, integral with band I6. The precise manner of electrically intercon-. -nesting-the elements forms no part of the invention.

disposed adjacent to one side of the tank and electrode 58 is disposed close to the opposite sideand that these two major operating parts may be in parallelism. It has been found that ex- 7 the face of the plate.

To fulfill concept of the invention, there is provided a plurality of tubes I8, arranged in spaced relation and having apertures 88 formedtherethrough in opposed relation to. the of plate I8. In the instance shown, tubes" are horizontally positioned andjoined at the ends by manifolds 82, one of which is in connection with supply pipe 88 that, is extended to any suitable compressor or source of air. A by-pass tube 88 connects supply pipe 84 with the lowermost end of manifold 82, so that even distribution of the air is obtained. Through such relation of parts, air under pressure enters one manifold 82 at the upper end, while the air enters the opposite manifold 82 at the lower end thereof.

This assembly, which comprises tubes 18 and manifolds 82, is removably secured in place by clips 88.- Apertures 88 are spaced apart along It has been made apparent that plate I8 is the length of each tube I8 and the space between these apertures progressively increases as the uppermost tube is reached. In other words, there are fewer holes in the tubes as the top of the tank is approached.

Due to gravity, heavier. parts of the bath usually remain at the bottom of the tank and the weaker solution collecting at the top does not permit of rapid and thorough actions. Recirculating the electrolyte or bath is also contemplated and combining the hereinafter men'- tioned meansfor re-circulating the bath with the-aforementioned means for introducing air under pressure has been found desirable. A pump 98 is employed to withdraw the electrolyte from points near the bottom of tank 8 and throughintake pim 82, joined to pump 88 by pipe 98. After the electrolyte is withdrawn it is re-introduced through pipe 96 and branch pipes 98 into the bath in the form of streams directed outwardly from branch-pipes 98 inpaths perpendicularto the plane of plate I8 and parallel to the jets of air emanating from apertures 88. Openings I88, formed in branch pipes 98, permit such action and the connection of pipe 96 with branch pipes 98 is made through the medium of manifold I82. The series of pipes 88 are spaced collection of foreign matter and polarization from' gases that otherwise would form around the cathode. Because heavyparticles collect at the bottom of tank 8, a pair of tubes I84 are directly connected to manifolds 82 and caused to lie in close proximity to the floor-of tank 8. oppositely directed apertures I88 formed through these tubes maintain constant agitation so that intake pipes 92 will carry some of the heavier particles back into the upper portion of. the bath.

As the temperature of the electrolyte changes, the action upon plate I8 is altered. It has been found necessary to maintain the bath at an even temperature so that the action is constant regardless of fluctuations of atmospheric temperature. An even temperature is maintained through the medium of an electrical heating element I88 that may be placed in tank 8 and connected to a thermostat II8 that is actuated by the change in temperature of the bath. Wires H2 and I connect thermostat'and heating element I I8 and I88 respectivelywith'lines H8 and H8 so that electrical energy may pass into the heating element I88 whenever the thermostat I I8 has closed its switch points.

" If it is desired to empty tank 8, valve I 28 may be closed and pump 88 allowed to force the bath out through branch pipe I22, instead of back through pipes 88. j

- Theoperation of an etching machine embodying-this'invention has been made clear during the course of the specification, and while one embodiment has been illustrated and described, it is desired to be limited only by the spirit of .the invention andscope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

' 1. In an etching machine of the kind described,

a tank for the electrolyte; a cathode suspended in the tank; a support to hold the plate being etched in a vertical position within the tank; a plurality of conduits arranged in'a vertical plane and having openings the mouths of which are in opposed spaced relation to the face of the plate being etched; a pump in connection with the conduits having an intake pipe extending into the tank at the bottom thereof for withdrawing electrolyte from the tank and directing it against the face of the plate being etched in horizontal streams through said openings; a plurality of tubes, disposed in a vertical plane within the tank between the conduits and the plate being etched, provided with apertures the mouths of which are in opposed spaced relation to the plate being etched; and a pipe, having connection with a source of compressed air, for forcing jets of air through said apertures, said stream of electrolyte and jets of air serving to move the electrolyte against the face of the plate being etched, said plate support being adjustable toward and from the conduits and pipes for the purpose specified, said cathode being disposed on the opposite side of the conduits and pipes from the plate support, said cathode being acontinuous bar bent to form a plurality of substantially U-shaped salients extending to one side of a straight line and all disposed in a vertical plane parallel with the plane of the plate being etched, the central salient being extended outwardly from said straight line a greater distance than the salients to each side thereof, whereby a greater or lesser amount of the cathode may be moved to a position below the surface of said electrolyte as the cathode is lowered or raised respectively.

2. In an etching machine of the kind described, a tank for the electrolyte; a cathode suspended in the tank; a plate support for the plate being etched vertically disposed within the tank; and adjustable elements for moving a greater or lesser amount of the cathode to position below the surface of said electrolyte. said cathode being movable in a vertical plane parallel to the plane of said plate support, the cathode being formed so that a progressively greater amount of both its width and length enter below the surface of the electrolyte as the cathode is lowered.

3. In an etching machine of the kind described, a tank for the electrolyte; a cathode suspended in the tank; a support in the tank for holding the plate being etched in a vertical plane; and adjustable elements for moving the cathode into and out of the electrolyte, said cathode being a continuous bar bent to form a plurality of substantially U-shaped salients extending to one side of a straight line and all disposed in a vertical plane parallel with the plane of the plate being etched.

4. In an etching machine of the kind described, a tank for the electrolyte; a cathode suspended in the tank; a support in the tank for holding 'the plate being etched in a vertical plane; and adjustable elements for moving the cathode into and out of the electrolyte, said cathode being a continuous bar bent to form a plurality of substantially U-shaped salients extending to one side of a straight line and all disposed in a vertical plane parallel with the plane of the plate being etched, the central salient being extended outwardly from said straight line a greater distance than the salient to each side thereof whereby upon lowering the cathode into the electrolyte, a greater portion of the bar forming the central salient is submerged as the bights of the remaining salients approach the surface of the electrolyte.

5. In an etching machine of the kind described, a tank for the electrolyte; a cathode suspended in the tank; a support in the tank for holding the plate being etched in a vertical plane; and adjustable elements for moving the cathode into and out of the electrolyte, said cathode being a continuous bar bent to form a plurality of substantially U-shaped salients extending to one.

remaining salients approach the surface of the electrolyte, the'ends of said bar being journalled in bearings to permit rectilinear reciprocation in the path of travel perpendicular to the horizontal surface of the electrolyte.

6. As a new article of manufacture, a cathode for etching machines comprising a continuous bar rebent to form a U-shaped body, the bight of said U-shaped body being further bent to create a plurality of salients all extending outwardly from a straight line joining the lower ends of thelegs of the U-shaped body, each of said salients being U-shaped and having the legs thereof spaced from the legs of the proximal salient, the central salient being extended outwardly from the straight line a greater distance than the salients to each side thereof.

'7. As a new article of manufacture, a cathode for etching machines comprising a continuous bar rebent to form a U-shaped body, the bight of said U-shaped body being further bent to create a plurality of salients all extending outwardly from a straight line joiningthe lower ends of the legs of the U-shaped body, each of said salients being U-shaped and having the legs thereof spaced from the legs of the proximal salient, the central salient being extended outwardly from the straight line a greater distance than the salients to each side thereof, all of said salients being in a common plane.

8. In an etching machine of the kind described, a tank for electrolyte; a cathode suspended in the tank; a plate support for the plate being etched; and pipes submerged in the electrolyte between the cathode and plate support, for directing jets of air under pressure toward the plate in directions perpendicular to the face thereof, said pipes being provided with holes for the escape of the air, the holes being spaced progressively farther apart as the surface of the electrolyte is approached. h

9. In an etching machine of the kind described, a tank for electrolyte; a cathode suspended in the tank; a plate support for the plate being etched; and pipes submerged in the electroof air in directions toward the cathode and indirections opposite to the holes in the pipesbelow the uppermost pipe.

10. In an etching machine of the kind described, a tank for electrolyte; a cathode susbeing etched; and pipes submerged in the electrolyte between the cathode and plate support, for directing jets of air under pressure toward .the plate in directions perpendicular to the face thereof, said pipes being provided with holes for the escape of the air, the hoiesbeing spaced '4 r a I 2,176,688

pended in the tank; a plate support for the plate- RAY W. HEHSLER. 

